Previous studies have suggested that dysregulation of RAI3 expression is associated with several malignancies, including increased RAI3 expression in colorectal (Kume et al. 2014; Zougman et al. 2013) and breast cancer (Jörißen et al. 2009) or decreased RAI3 expression in oral squamous cell (Liu et al. 2013), non-small cell lung (Fujimoto et al. 2012), hepatocellular (Zheng et al. 2014), and gastric cancer (Cheng et al. 2012). Here, GPRC5A is linked to gastric cancer.